Aflatoxin is produced by the action of a fungi belonging to the genus, Asperigillus, on exposed grain seeds or nuts. Aflatoxin affects certain grains such as corn, hops, cottonseed, soybean, and the like, as well as such nuts as almonds, Brazil nuts, pecans, pistachios, peanuts, and the like, and is particularly active and dominant when such grains and nuts are grown and cultivated in wet climates.
Due to the toxic threat that aflatoxin-contaminated food sources present to animals, there have been many attempts to treat grains and nuts in meal form so as to either detoxify these food sources or lower the level of their aflatoxin-contamination. Representative of such attempts are the use of photochemical means to detoxify the aflatoxin-contaminated food sources (U.S. Pat. No. 3,506,452), mixing the food source product with methylamine at elevated temperatures (U.S. Pat. No. 3,585,041), contacting the food source product with ozone (U.S. Pat. No. 3,592,641), treating suspension of the food product with peroxide (British Pat. No. 1,117,573), treating the food products with various aromatic solvents such as aqueous isopropanol (E. T. Raynor et al., J. Amer. Oil. Chem. Soc., 1968, 45 (9) pp. 622-4), aqueous ethanol (E. T. Raynor et al., J. Amer. Oil Chem. Soc., 1970, 47 (1), 26 Chem. Abstracts, 72:6847z), an actone-hexane-water-azeotrope mixture (U.S. Pat. No. 3,515,736), and aqueous acetone followed by hexane extraction (U.S. Pat. No. 3,557,168).
Treatment of aflatoxin-contaminated food source products with strong alkaline based solutions at elevated temperatures for extended periods of time has also been attempted. One such method involves treating hydrated peanut meal in the presence of either ammonia or methylamine or sodium hydroxide or ozone to reduce the aflatoxin content to less than about thrity parts per billion (ppb) followed by extraction of the peanut meal with 90% acetone-10% water to produce a peanut meal free of aflatoxin (F. G. Dollear et al, "Elimination of Aflatoxins from Peanut Meal", J. Amer. Oil Chem. Soc., 45 (12), pp. 862-5 (1968), Chem. Abstracts, 70:76557 (1969)). In another effort, afflatoxin in peanut meal was reduced by contacting the peanut meal with either ammonia or methyl ammonia or sodium hydroxide or bicarbonate (G. E. Mann et al, "Chemical Inactivation of Aflatoxin in Peanut and Cottonseed Meals", J. Amer. Oil. Chem. Soc., 45 (5) pp. 173-61 (1970), Chem. Abstracts, 73:23929 (1970)). Still another attempt involves innoculating a growth media with a commercial bleach such as Clorox containing sodium hyperchlorite at various concentrations (C. Y. Young, "Comparative Studies on the Detoxification of Aflatoxins by Sodium Hypochlorite and Commercial Bleashes", Appl. Microbiol., 24 (6) pp. 885-90 (1972), Chem. Abstracts, 78:80617 (1973)). More recently, aflatoxin contaminated oilseed meal products have been treated with a mixture of an alkali or alkaline earth metal and an organic amine (U.S. Pat. No. 3,890,452).
One method of particular interest involves cooking peanut meal in a two percent solution of sodium hydroxide for two hours at a temperature of 100.degree. C in order to reduce the aflatoxin content to 18 ug/kg. When the peanut meal was cooked for 1.5 hours at 212.degree. F, the aflatoxin was reduced to 9 ug/kg. (F. G. Dollear, "Detoxification of Aflatoxins in Foods and Feeds", Sci. Bkgrnd. Cntrl. & Imp., edited by L. A. Goldblatt, Academic Press, N.Y. (1969) pp. 359-91, Chem. Abstracts, 76:68783 (1972)).
It is significant to note that the prior art methods and processes referred to and described above all attempt to provide means for complete detoxification and use grains or nuts which have been ground to meal form. It will also be noted that these prior art methods involve prolonged, sometimes complex and often costly procedures, especially where the grains or nuts must be defatted and then ground to meal form before being subjected to these processes.
It would be desirable, therefore, to provide a simple, easy and economical means for substantially eliminating aflatoxin-contaminated grain seeds or nuts from uncontaminated grain seeds or nuts thereby permitting these uncontaminated grain seeds or nuts to be safely used as a source supply for food products.